SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8c00c230df82e4607619e39758a97d67936be58d1833a8fed1e2fd938cf2582' 
  AND token = 'HY2xJiHNTPHmelDkZVTVPjJsCYK6bVZlsAC7CIn/lWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}